Production of saturated dicyclic hydrocarbons



Dec. 19, 1967 Y L, E. DREHMAN 3,359,338v

PRODUCTION OF SATURATED DICYCLIC HYDROCARBONS Filed Sept. 28, 1960 A TTORNEVS United States Patent() 3,359,338 PRODUCTION OF SATURATED DICYCLIC HYDROCARBONS Lewis E. Drehman, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Sept. 28, 1960, Ser. No. 59,093 10 Claims. (Cl. 260-666) This invention relates to the production of saturated dicyclic hydrocarbons.

The advent of turbo-jet engines, ram jets, and liquid fuel rocket engines has resulted in the development and commercialization of several grades of jet fuels, most of which are kerosene grade hydrocarbons. The most widely used grade is currently designated as JP-4, although other grades such as JP-S have been employed. These relatively inexpensive hydrocarbon fuels have, in general, proved to be satisfactory, but it would be very desirable if higher density hydrocarbons having higher heats of combustion were available.

The development of supersonic aircraft with ultrathin wing sections has practically eliminated the use of internal wing space for the storage of fuel. This limitation seriously reduces the range of high speed aircraft as only a limited number of gallons of fuel can be stored in the fuselage. Thus, if higher density hydrocarbon fuels with essentially the same heat of combusion in B.t.u.s per pound were available a tank of given volume could store more energy and more thrust would be available. If said higher density fuels also have a higher heat of combustion, then the gain in thrust is even greater.

Accordingly, an object of this invention is to provide a process for the production and recovery of saturated dicyclic hydrocarbons.

Another object of this invention is to provide a new source of high density jet engine fuel.

Other objects, advantages and features of my invention will be readily apparent to those skilled in the art from the following description and the appended claims.

Broadly, parafin hydrocarbons, preferably normal paraffins, of at least 7 carbon atoms and boiling below 400 F. are combined with methylcyclopentane and/or cyclohexane and the combined hydrocarbons contacted under severe isomerization conditions with an aluminum chloride-hydrocarbon complex catalyst. Saturated dicyclic hydrocarbons boiling above 400 F. are recovered from the hydrocarbon effluent, said dicyclic hydrocarbons suitably employed as high density jet fuels.

It is important in the practice of the inventive process that naphthenes having 7 or more carbon atoms be substantially removed from the paraffin feed as these naphthenes are effective disproportionation inhibitors. A conventional solvent extraction method employing a selective solvent, such as furfural or methyl carbitol, can be utilized to remove the C7+ naphthenes. Removal can also be accomplished, for example, by a conventional azeotropic distillation process.

The paraffin feed should also be free of aromatics as it is well known in the art that aromatics are also effective disproportionation inhibitors. A conventional method of removing aromatics consists of employing a polar solvent such as diethylene glycol monomethylether to selectively extract said aromatics from the parailin hydrocarbon feed material.

In addition to the paran feed materials heretofore described, the hydrocarbon feed will normally contain l to 50 weight percent methylcyclopentane and/or cyclohexane, although a greater proportion of methylcyclopentane and/ or cyclohexane can be utilized.

The term severe isomerization conditions refers to those conditions wherein at least weight percent, pref- Patented Dec. 19, 1967 erably at least 10 weight percent, of the hydrocarbon charge is converted to butane and lighter.

The accompanying drawing is a diagrammatic flow sheet illustrating one embodiment of the invention. In said drawing, all pumps, coolers, heaters, condensers, valves, surge vessels, etc., have been omitted in order to simplify the explanation thereof. However, it is to be understood that the process of the invention includes such auxiliary equipment of this type which is necessary for the operation thereof and, in addition, includes the apparatus necessary to provide reflux to the top of the fractionating tower and heat to the bottom of the fractionating tower, which heat and reflux are necessary for the separation being carried out in the fractionating tower.

Referring now to said drawing, the invention will be more fully explained. A hydrocarbon feed stream comprising paraffin hydrocarbons of at least 7 carbon atoms and boiling below 400 F., is passed via conduit 10 to absorber 11. Within absorber 11, the hydrocarbon feed stream is countercurrently contacted with a selective solvent such as furfural introduced to absorber 11 via conduit 12. A solvent stream containing C74' naphthenes present in the hydrocarbon feed stream to the absorber 11 is removed from absorber 11 via conduit 13 for further processing not herein described. A parain hydrocarbon stream is removed from absorber 11 via conduit 14 wherein said paraffin hydrocarbon stream is mixed with methylcyclopentane and/or cyclohexane, the combined hydrocarbon stream consisting of 10 to 50 weight percent methylcyclopentane and/or cyclohexane passed to conduit 14 via conduit 15. Other means of mixing the two streams than herein noted are, of course, within the scope of this invention.

The combined feed stream is passed via conduit 14 through dehydrator 15 wherein substantially all the moisture present in said combined feed stream is removed. Normally two dehydrators are operated in parallel with one dehydrator being in operation while the other dehydrator is being regenerated or being emptied and filled with fresh drying agent. Any suitable drying agent can be employed, with bauxite usually preferred.

The dried feed stream is passed via conduit 16 through one or more of the various inlets into aluminum chloride chamber 17. In said chamber 17 said feed stream contacts powdered aluminum chloride which is picked up and carried with the feed through conduits 18, 19 and 20 into isomerization reactor 21. The amount of fresh aluminum chloride suspended in said feed stream can be controlled by passing a portion or all of said feed stream through conduit 22 into said conduit 19, thus by-passing chamber 17. Before entering said reactor 21, the catalyst concentration of the feed is increased by the addition of aluminum chloride-hydrocarbon complex catalyst from conduit 23 and settler 24.

The aluminum chloride-hydrocarbon complex catalyst can be originally prepared by mixing aluminum chloride and kerosene in a weight ratio of about 8 to 5. During operation of the process, the original complex catalyst is replaced with complex catalyst formed in the process with a concentration of aluminum chloride in the range of 55-70 weight percent. Hydrogen chloride is added to said reactor 21 via conduit 25 from a source hereinafter described so as to maintain a concentration of hydrogen chloride in the reaction zone of at least 2 weight percent of the hydrocarbon phase.

The temperature of reactor 21 is maintained in the range of l0() to 350 F. The volume of catalyst in the reaction mixture is maintained within the range of 25 to 50 percent. Reactor 21 is operated at a pressure sufficient to maintain a liquid phase reaction. The reaction time is 3 normally over 5 minutes and less than 2 hours, 15 to 45 minutes being a representative range. The described severe isomerization conditions maintained within reactor 21 provide a hydrocarbon efliuent with at least 5 weight percent of said eiuent as butane and lighter.

The eiuent from reactor 21 is passed via conduit 26 into settler 24 wherein the major portion of the catalyst complex is separated from the hydrocarbon material. The major portion of the separated or settled catalyst complex is returned via conduits 23 and 20 to said reactor 21 as previously described. Inasmuch as a catalyst complex gradually increases in volume, it is desirable that a portion thereof be either periodically or continuously withdrawn from the system. For this purpose, a bafiie is provided in one end of settler 24 to effect a quiescent zone and separated catalyst complex can be withdrawn from settler 24 via conduit 27.

Although a substantial separation of the catalyst complex and hydrocarbon is effected in settler 24, the hydrocarbon layer still contains some finely divided suspended catalyst complex and a major portion of the hydrogen chloride, Said hydrocarbon layer is Withdrawn from settler 24 via conduit 28 and introduced into the upper portion of coalescer 29. Said coalescer 29 contains a bed of particulate materials such as anthracite coal, ceramic chips, raschig rings, bauxite, etc., which provides the surface for the entrained yet suspended finely divided aluminum chloride hydrocarbon complex catalyst to coalesce on. Although only coalescer 29 has been shown in the drawing, it will be understood that two or more such coalescers can be operated in parallel similarly as described above in connection with dehydrator 15.-It is also within the scope of the process to employ two or more coalescers in series. Coalesced catalyst complex collects in the bottom of coalescer 29 and is withdrawn therefrom via conduit 30.

A hydrocarbon layer, now essentially free of entrained catalyst complex, is passed via conduit 31 into HCl stripper 32 wherein substantially all of the hydrogen chloride is separated from the hydrocarbons. The overhead stream from said HCl stripper 32 is a hydrogen chloride rich stream which, as previously described, is passed via conduit 25 into isomerization reactor 21. Make-up hydrogen chloride can be introduced into the system via conduit 33 from a source not herein shown.

4 moved from said tower 37 via conduit 38. Although only one sand tower 37 has been shown, two or more such towers can be employed in parallel in the manner described above in connection with dehydrator 15 so as to provide for continuous operation.

A hydrocarbon stream is passed via conduit 39 from sand tower 37 into fractionator 40. In said fractionator 40, the hydrocarbon feed stream is fractionated and a saturated dicyclic hydrocarbon containing stream boiling above 400 F. is recovered from the bottom of fractionator 40 via conduit 41. An overhead product stream boiling below 400 F. is recovered from fractionator 40 via conduit 42.

The following examples will serve to illustrate the invention.

Example I A run was made in which a 1/2 weight blend of cyclohexane/ n-octane was contacted for 15 minutes at 206 F. with an aluminum chloride-hydrocarbon complex and an hydrous HCl. The aluminum chloride-hydrocarbon complex contained 58 weight percent aluminum chloride. The feed-to-catalyst volume ratio was 1.73. The HC1 charged was 7.5 pounds per 100 pounds of hydrocarbon, which gave a concentration of about 2.5 weight percent in the hydrocarbon phase. The remainder of the HCl was dissolved in the complex. The reaction was carried out batchwise in a stirred autoclave.

The hydrocarbon product contained 12.6 weight percent of material boiling above normal octane. Of this heavy fraction, 44 percent boiled in the gasoline range. An additional 40 percent of the heavy fraction boiled principally between 419 F. and 437 F. Two heart cuts (82% of the 40%) of this second portion of the heavy fraction were analyzed and contained 1.4 liquid volume percent paraiiins, 16.3 percent monocyclic naphthenes, 81.7% dicyclic naphthenes and 0.6 percent aromatics. The remaining 16 percent of the heavy fraction boiled above 482 F., containing a high proportion of polycyclics.

Example II The following runs illustrate the undesirably effective disproportionation suppression of methylcyclohexane (MCH) compared to that of methylcyclopentane (MCP) when practicing the inventive process, MC-H providing low yields of higher boiling products.

Run No.

Naphthene feed Wt. percent Naphthene in feed HC1, Wt. percent of hydrocarbon feed Feed/Complex Volume ratio Reaction temperature, F Reactor Pressure, p.s.1

Stirring time, minutes Parafn isomerized, Wt. percen Paraftin destroyed, Wt. percent.. Naphthene isomerized, Wt. percent.-- Naphthene destroyed, Wt. percent Products, Wt. percent of total feed:

C4s and lighter iCs-n-paran charged Heaver than paraffin charged Complexed Composition ofoeavy Ends, Vol. percent; 1

Heptane He tane M P P Heptane MGP Heptane man 1 05+ fractions of Runs 1, 2, 3 and 4 were combined before the fractional analysis shown.

A bottoms product from HC1 stripper 32 is removed therefrom via conduit 34 and introduced into caustic washer 35 wherein remaining traces of hydrogen chloride are neutralized. The caustic washed hydrocarbon product is then passed via conduit 36 into tower 37 which contains a bed of sand, or other similar particulate material,

Example Ill The following run illustrates that only low yields of products heavier than the feed parafiin are obtained when hexane and lighter parains are converted in the presence of aluminum chloride-hydrocarbon complex and a C6 to remove entrained caustic. Entrained caustic can be renaphthene.

Parain feed Hexane Products-wt. percent of total feed:

C4s and lighter 0 iC5-n-parain charged 98.8 Heavier than n-parain charged 1.2 Complexed 0.5 Composition of heavy ends-vol. percent:

Cqs (8S-100 C.) 6.0 Cs (100l30 C.) 50.0 C9s (13G-150 C.) 4.0 Cms (ISO-175 C.) 2.0 Cus (U5-200 C.) 1.5 C124' (200 C.`-{) includes dicyclics 36.5

The comparison of the results obtained in Examples I, II, and III conclusively illustrate that significantly increased yields of dicyclic saturated hydrocarbons are produced with a feed material comprising Cq+ paraflin hydrocarbons and methylcyclopentane as opposed to a feed material containing methylcyclohexane and/o1' paran hydrocarbons containing less than 7 carbon atoms.

As will be evident to those skilled in the art, various modifications of this invention can be made, or followed, in the light of the foregoing disclosure and discussion Without departing from the spirit or scope thereof.

I claim:

1. A process for the production of saturated dicyclic hydrocarbons which comprises contacting a hydrocarbon feed mixture with an aluminum chloride-hydrocarbon complex catalyst and HC1 in a reaction zone, said hydrocarbon feed mixture consisting essentially of parain hydrocarbons boiling below 400 F. and at least one naphthene selected from the group consisting or methylcyclopentane and cyclohexane, said parain hydrocarbons having at least seven carbon atoms maintaining severe isomerization conditions within said reaction zone, and withdrawing from said reaction zone an effluent hydrocarbon stream containing saturated dicyclic hydrocarbons.

2. A process for the production of saturated dicyclic hydrocarbons which comprises contacting a hydrocarbon feed mixture with an aluminum chloride-hydrocarbon complex catalyst and HC1 in a reaction zone, said hydrocarbon feed mixture consisting essentially of parafln hydrocarbons boiling below 400 F. and at least one naphthene hydrocarbon selected from the group consisting of methylcyclopentane and cyclohexane, said parain hydrocarbons having at least seven carbon atoms maintaining severe isomerization conditions within said reaction zone, withdrawing from said reaction zone an eiluent hydrocarbon stream, passing said euent hydrocarbon stream into a fractionation zone, withdrawing from said fractionation zone a light hydrocarbon stream boiling below 400 F., and withdrawing from said fractionation zone a hydrocarbon stream containing saturated dicyclic hydrocarbons and boiling above 400 F.

3. A process for the production of saturated dicyclic hydrocarbons which comprises introducing into a reaction zone a hydrocarbon feed mixture consisting essentially of paratlin hydrocarbons boiling below 400 F. and at least one naphthene hydrocarbon selected from the group consisting of methylcyclopentane and cyclohexane, said paraffin hydrocarbons having at least seven carbon atoms contacting said hydrocarbon feed mixture.

with HC1 and an aluminum chloride-hydrocarbon cornplex containing a concentration of 55-70 weight percent of aluminum chloride, maintaining in said reaction zone a catalyst concentration in the range of 25-50 volume percent in the reaction mixture, maintaining the temperature of said reaction zone in the range of 1D0-350 F., maintaining a pressure within said reaction zone so as to provide a liquid phase reaction, and withdrawing from said reaction zone an eflluent hydrocarbon stream containing saturated dicyclic hydrocarbons.

4. The process of claim 3 wherein the concentration of naphthene hydrocarbons in said hydrocarbons feed mixture is in the range of 10-50 weight percent.

5. The process of claim 4 wherein the concentration of HCl in the reaction zone is at least two weight percent of the hydrocarbon phase.

6. The process of claim 4 wherein the time of contact within said reaction Zone is in the range from 5 minutes to 2 hours.

7. A process for the production of saturated dicyclic hydrocarbons which comprises introducing into a reaction zone a hydrocarbon feed mixture consisting essentially of paraffin hydrocarbons boiling below 400 F. and at least one naphthene hydrocarbon selected from the group consisting of methylcyclopentane and cyclohexane, said paraiiin hydrocarbons having at least seven carbon atoms contacting said hydrocarbon feed mixture within said reaction Zone with HCl and an aluminum chloride-hydrocarbon complex catalyst containing a concentration of 55-70 weight percent of aluminum chloride, maintaining a catalyst concentration in the range of 25-50 volume percent in the reaction mixture within said reaction zone, maintaining the temperature of said reaction zone in the range of 1D0-350 F., maintaining a concentration of HCl in said reaction zone of at least 2 weight percent of the hydrocarbon phase, maintaining a pressure within said reaction zone so as to provide a liquid phase reaction, withdrawing from said reaction zone an effluent stream, passing said efliuent stream to a settling zone wherein aluminum chloride-hydrocarbon complex catalyst is permitted to settle in a separate phase, passing a hydrocarbon stream from said settling zone to a c0- alescing zone wherein entrained aluminum chloride catalyst is removed from said hydrocarbon stream, passing a hydrocarbon stream from said coalescing zone to a stripping zone wherein HCl is separated from said hydrocarbon stream, passing a hydrocarbon stream from said stripping zone to a caustic wash zone, passing a hydrocarbon stream from said caustic wash zone to a filtering zone wherein entrained caustic wash solution is separated from said hydrocarbon stream, passing a hydrocarbon stream into a fractionation zone, withdrawing from said fractionation zone a light hydrocarbon stream boiling below 400 F., and withdrawing from said fractionation zone a hydrocarbon stream containing saturated dicyclic hydrocarbons boiling above 400 F.

8. A process for the production of saturated dicyclic hydrocarbons which comprises introducing into a separation zone a C7+ hydrocarbon feed mixture consisting essentially of napthene hydrocarbons and parat-lin hydrocarbons boiling below 400 F., withdrawing from said separation zone a napthene-free hydrocarbon stream, combining said naphthene-free hydrocarbon stream with a naphthene hydrocarbon selected from the group consisting of methylcyclopentane and cyclohexane, passing said combined stream to a reaction zone, contacting said combined stream within said reaction zone with HC1 and aluminum chloride-hydrocarbon complex catalyst containing a concentration of 55-70 weight percent of aluminum chloride, maintaining a catalyst concentration in the reaction mixture in the range of 25-50 volume percent, maintaining the temperature of said reaction zone in the range of -350 F., maintaining the pressure within said reaction zone so as to provide a liquid phase reaction, maintaining a concentrating of HCl in said reaction zone of at least 2 weight percent of the hydrocarbon phase, and withdrawing from said reaction zone an efuent-hydrocarbon stream containing saturated dicyclic hydrocarbons.

9. A process for the production of saturated dicyclic hydrocarbons which comprises introducing into a separation zone a C7+ hydrocarbon feed mixture comprising naphthene hydrocarbons and paratlin hydrocarbons boiling below 400 F., withdrawing from said separation zone a naphthene-ree hydrocarbon stream, combining said naphthene-ree hydrocarbon stream with a naphthene hydrocarbon selected from the group consisting of methylcyclopentane and cyclohexane, passing said cornbined hydrocarbon stream to a reaction zone, contacting said combined hydrocarbon stream in said reaction zone with HC1 and aluminum chloride-hydrocarbon complex catalyst containing a concentration of 5570 Weight percent of aluminum chloride, maintaining a catalyst concentration in said reaction mixture in the range of 25-50 volume percent, maintaining a concentration of HC1 in the reaction zone of at least 2 weight percent of the hydrocarbon phase, maintaining the temperature of said reaction zone in the range of 10U-350 F., maintaining a pressure within said reaction zone so as to produce a liquid phase reaction process, withdrawing from said reaction zone an etliuent stream, passing said eluent stream to a settling zone wherein aluminum chloridehydrocarbon complex catalyst is permitted to settle in a separate phase, passing a hydrocarbon stream from said settling zone to a coalescing zone wherein entrained aluminum chloride is separated from said hydrocarbon stream, passing a hydrocarbon stream from said coalescing zone to a HC1 stripping zone, passing a hydrocarbon stream from said stripping zone to a caustic wash zone, passing a hydrocarbon stream from said caustic wash zone to a filtering zone wherein entrained caustic solution is removed from said hydrocarbon stream, passing a hydrocarbon stream from said ltering zone to a fractionation zone, withdrawing from said fractionation zone a light hydrocarbon stream boiling below 400 F., and withdrawing from said fractionation zone a hydrocarbon stream containing dicyclic hydrocarbons boiling above 400 F.

10. Method for preparing saturated dicyclic hydrocarbons which comprises contacting a mixture of a C6 naphthene and a parain hydrocarbon having at least 7 carbon atoms at a temperature in the range of F. to 350 F. with HCl and a catalyst complex obtained by contacting a hydrocarbon with aluminum chloride.

References Cited UNITED STATES PATENTS 2,387,989 10/1945 Foster 260--666 2,415,066 l/l947 Ross et al. 260-666 2,420,086 5/1947 McAllister et al 260-666 2,423,045 6/1947 Passino et al. 208--135 2,474,827 7/1949 Condon 260--666 2,562,926 8/1951 Legatski 260-666 3,104,266 9/1963 KrOn 260-666 PAUL M. COUGHLAN, JR., Primary Examiner.

ALPHONSO D. SULLIVAN, DANIEL E. WYMAN,

DELBERT E. GANTZ, Examiners.

C. R. DAVIS, C. E. SPRESSER, P. P. GARVIN,

Assistant Examiners. 

3. A PROCESS FOR THE PRODUCTION OF SATURATED DICYCLIC HYDROCARBONS WHICH COMPRISES INTRODUCING INTO A REACTION ZONE A HYDROCARBON FEED MIXTURE CONSISTING ESSENTIALLY OF PARAFFIN HYDROCARBONS BOILING BELOW 400*F. AND AT LEAST ONE NAPHTENE HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF METHYLCYLOPENTANE AND CYCLOHEXANE, SAID PARAFFIN HYDROCARBONS HAVING AT LEAST SEVEN CARBON ATOMS CONTACTING SAID HYDROCARBON FEED MIXTURE WITH HCL AND AN ALUMINUM CHLORIDE-HYDROCARBON COMPLEX CONTAINING A CONCENTRATION OF 55-70 WEIGHT PERCENT OF ALUMINUM CHLORIDE, MAINTAINING IN SAID REACTION ZONE A CATALYST CONCENTRATION IN THE RANGE OF 25-50 VOLUME PERCENT IN THE REACTION MIXTURE, MAINTAINING THE TEMPERATURE OF SAID REACTION ZONE IN THE RANGE OF 100-350*F., MAINTAINING A JPRESSURE WITHIN SAID REACTION ZONE SO AS TO PROVIDE A LIQUID PHASE REACTION, AND WITHDRAWING FROM SAID REACTION ZONE AN EFFLUENT HYDROCARBON STREAM CONTAINING SATURATED DICYCLIC HYDROCARBONS. 